Control device

ABSTRACT

A control device ( 100 ) for controlling a control subject ( 2 ), said control device being equipped with: an instruction value generation part ( 20 ) that calculates an instruction value from an instruction pattern; a learning control part ( 30 ) that repeatedly calculates correction data containing a correction value for correcting the instruction value calculated from the instruction pattern; and a control part ( 10 ) that calculates a corrected instruction value from the instruction value and the correction data, and transmits the corrected instruction value to the control subject. The learning control part ( 30 ) generates the correction data from a response delay characteristic of the control subject, and the deviation between a feedback value for the corrected instruction value that has been output for the control subject and the instruction value that has been calculated by the instruction value generation part ( 20 ).

TECHNICAL FIELD

This invention relates to a control device which controls a controlsubject using a control instruction through learning control withimproved control performance.

BACKGROUND ART

There is a general method of modeling a control subject and calculatinga feed-forward input on the basis of a parameter used in identificationof a system of the control subject. A learning control method is knownas a method in which, when it is difficult for a control subject toprecisely calculate a parameter value, a feed-forward input is correctedwhile trials are actually repeated to -realize a target output.

In control of a dynamic system that includes an unknown element as acontrol subject, learning control is used particularly in control ofmechanical systems that use robots and motors.

Patent Literature 1 discloses a numerical control device which takesposition deviation data and correction data in each period and performslearning computation using the position deviation data. Accordingly, thenumerical control device is disclosed to perform learning control at anarbitrary position at which processing for the same shape is performed,then a position deviation is acquired, and thereby highly preciseprocessing can be realized.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Unexamined Patent Application PublicationNo. 2004-227163 (published on Aug. 12, 2004)

SUMMARY OF INVENTION Problem to be Solved by Invention

However, in order to improve control performance through learningcontrol, it is necessary to appropriately set a cormorant parameter tobe used in the learning control.

The control device disclosed in Patent Literature 1 described abovecalculates a correction value that may reduce a target deviationquantity. However, this correction value does not reflectcharacteristics of the control subject. Thus, there is concern ofcontrol performance falling short of a target performance due to aparameter inappropriately set for the learning control. The adjustmentof the parameter for learning control and the calculation of thecorrection value performed while trial and error is performed may hindera prompt start of a control system including the control device.

The present invention aims to provide a control device that can easilycalculate a parameter to be used in learning control suitable for acontrol subject.

Solution to Problem

To solve the above-described problem, the control device according tothe present invention is a control device that controls a controlsubject and is characterized by including an instruction valuegeneration part that calculates an instruction value from an instructionpattern, a leaning control part that repeatedly calculates correctiondata including a correction value for correcting the instruction valuecalculated from the instruction pattern, and a control part thatcalculates a corrected instruction value from the instruction value andthe correction data and transmits the corrected instruction value to thecontrol subject, and the learning control part generates the correctiondata from a deviation between a feedback value with respect to thecorrected instruction value output to the control subject and theinstruction value computed by the instruction value generation part anda response delay characteristic of the control subject.

Advantageous Effects of Invention

According to the present invention, a control device that performslearning control which can easily obtain a parameter of a controlsubject to be used in learning control and improve control performancecan be acquired.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing an overall configuration of a controlsystem.

FIG. 2 is a diagram showing a hardware configuration of a controldevice.

FIG. 3 is a diagram showing a flowchart of an operation of the controldevice 100.

FIG. 4 is a diagram showing a flowchart of an operation of the controldevice 100.

FIG. 5 is a diagram showing a flowchart of an operation of the controldevice 100.

FIG. 6 is a diagram showing calculation of a correction shift time froma characteristic measurement parameter.

FIG. 7 shows graphs showing results of learning control performed usinga learning control parameter.

FIG. 8 is a diagram showing results of learning performed in differentcorrection shift times.

FIG. 9 is a block diagram showing a functional configuration of thecontrol device.

FIG. 10 is a diagram showing an example of a library program executed bythe control device according to the embodiment.

FIG. 11 is a diagram showing an example of the library program executedby the control device according to the embodiment.

DESCRIPTION OF EMBODIMENTS

An embodiment of a control device 100 according to the present inventionwill be described below in detail with reference to the drawings. Itshould be noted that the embodiment does not limit the presentinvention.

Embodiment 1 Overall Configuration of Control System

FIG. 1 is a block diagram showing a configuration of a control systemincluding the control device 100 according to an embodiment of thepresent invention. In this drawing, the control system includes thecontrol device 100 according to the present embodiment and a controlsubject 2. The control device 100 is typically a PLC (programmablecontroller), and computes control outputs to control control subjects.The control device 100 computes a control output from a feedback valuethat is a result of a control subject controlled in each predeterminedcontrol period. The control subject 2 is typically a machine that isdriven by an actuator serving as a drive control device, is inputted acontrol output computed by the control device 100, and is driven inaccordance with the control output. The control subject driven inaccordance with the control output outputs a driving position, speed,and the like to the control device 100 as feedback values via an encoder(not illustrated) and the like.

An example of the control system that controls tracks in accordance withan instruction pattern by performing position control will be describedbelow in the embodiment of the present invention.

Although an example in which a control subject is driven using a motorwill be described in the present embodiment, the invention is notlimited thereto as long as the control device 100 performs control, andthe control subject may be, for example, a temperature control devicethat controls temperature.

Hardware Configuration of Control Device

Next, a hardware configuration of the control device 100 will bedescribed. FIG. 2 is a schematic diagram showing an example of ahardware configuration of the control device 100 shown in FIG. 1.Referring to FIG. 2, the control device 100 implements control over acontrol subject when a processor executes a program installed inadvance. More specifically, the control device 100 includes a processor102 such as a central processing unit (CPU) or a micro-processing unit(MPU), a chipset 104, a main memory 106, a flash memory 108, an externalnetwork controller 116, a memory card interface 118, an internal buscontroller 122, and a field bus controller 124.

The processor 102 reads a system program 110 and a user program 112stored in the flash memory 108, develops the programs in the main memory106 to execute the programs, and thereby realizes control over a controlsubject. The system program 110 includes instruction codes for providingbasic functions of the control device 100, such as data input and outputprocesses or execution timing control. In the present embodiment, thesystem program 110 includes a library program 110A. The library program110A is stored by a reusable form in a general processes, and calls(call/invoke) the processes if necessary when the user program 112 isexecuted. That is, the library program 110A is used in execution of aprogram of the control device 100.

The user program 112 is arbitrarily designed in accordance with acontrol subject, and includes a sequence program 112A for executingsequence control and a motion program 112B for executing motion control.The sequence program 112A and the motion program 112B are executed byappropriately calling the library program 110A.

The chipset 104 realizes overall processes of the control device 100 bycontrolling each of the components.

The internal bus controller 122 is an interface for exchanging data withan I/O unit 126 that is connected to the control device 100 via aninternal bus. The field bus controller 124 is an interface forexchanging data with an I/O unit 128 that is connected to the controldevice 100 via a field bus 130 (FIG. 2). The internal bus controller 122and the field bus controller 124 acquire status values each input to thecorresponding I/O units 126 and 128, and output computation results ofthe processor 102 as instruction values from each of the correspondingI/O units 126 and 128.

The external network controller 116 controls exchange of data throughvarious types of wired or wireless networks. The memory card interface118 is designed such that a memory card 120 can be detached therefrom,and data can be written in and read from the memory card 120therethrough.

Some or all of functions provided when the control device 100 executesprograms may be implemented by dedicated hardware circuits.

Operation of Control Device for Learning Control

FIG. 3 shows a flowchart of an operation of the control device 100 whena learning control program according to the present embodiment isexecuted. When the learning control program is executed, the controldevice 100 repeatedly calculates correction values for giving desirableoutputs using deviation data before a trial.

A learning control parameter is read from a memory in S1. The learningcontrol parameter is a parameter that can be changed in accordance witha characteristic of a control subject controlled by the control device100, and includes a correction shift time which will be described below.

An instruction value is calculated from an instruction pattern in S2. Aninstruction value to be output to a motor control device in each controlperiod is calculated from the instruction pattern prescribed in the userprogram. The instruction pattern is a pattern that defines an operationof a target control subject. The instruction pattern is typically dataindicating temporal change in positions of a control subject moving froma specific position to another specific position. The control device 100calculates a position instruction value from the instruction pattern tobe given to the motor control device in each control period.

An instruction value to be output in each control period is calculatedusing a K-th piece of correction data in S3. The control device 100reads the correction data stored in the memory, adds the read correctiondata to the instruction value to correct the instruction value, andthereby obtains a corrected instruction value.

The corrected instruction value that has been corrected in each controlperiod is output to the motor control device in S4. The control device100 sequentially reads the instruction value corrected in S3 and outputsthe corrected instruction value to the motor control device. At the sametime, feedback data is acquired from the control subject andsequentially stored in the memory.

A K+1-th piece of correction data is calculated from the stored feedbackdata, the instruction value of each control period, and the learningcontrol parameter in S5. The control device 100 calculates deviationdata of the stored feedback data and the instruction value of eachcontrol period, and calculates the K+1-th piece of correction data,using Expression 1 which will be described below, using a correctionshift time from the learning control parameter read into the deviationdata. By repeatedly executing this series of processes, correction datathat is likely to approach an instruction pattern that defines anoperation of a target control subject is repeatedly calculated.

In S6, the control device 100 evaluates K pieces of the correction datacalculated as results of the learning, and selects and stores mostappropriate correction data using a predetermined evaluation function.Specifically, the control device 100 acquires the sum of squares of a1^(st) to a K-th position deviations, and when a decrease rate of thesum of the squares of the position deviations is lower than or equal toa predetermined value, the learning control ends. A method of evaluatinglearning results is not limited to this technique, and for example,correction data that has a minimum sum of squares of position deviationsaccording to a result of learning performed a predetermined number oftimes may be selected. In a case in which a level of approach of thecorrection data to a target value is set as a condition for endinglearning control, even if learning control is repeatedly performed andcorrection data is obtained, the correction data does not necessarilyapproach a target instruction value, and thus useless learning controlcomputation can be avoided.

Operation of Control Device when Calculation of Learning ControlParameter is Executed

FIG. 4 shows a flowchart of an operation of the control device 100 whena learning control parameter computation program is executed. When thelearning control parameter computation program is executed, the controldevice 100 calculates a correction shift time included in learningcontrol parameters by acquiring response characteristic data of acontrol subject device.

When the learning control parameter computation program is executed, thecontrol device 100 reads a characteristic measurement instructionpattern and calculates a characteristic measurement instruction value inS11. Here, the characteristic measurement instruction pattern mentionedmay be any instruction pattern as long as it is an instruction patternin which a response characteristic of a control subject with respect toan instruction value can be calculated, and may be a unit pulse, a stepfunction, or a ramp function.

In S12, the control device 100 outputs the characteristic measurementinstruction value calculated in each control period, and takes andstores a feedback value of each control period.

In S13, the control device 100 acquires response characteristic data ofthe control subject from the characteristic measurement instructionvalue and the feedback value of each control period. In the embodimentof the present invention, response characteristic data is acquired fromthe feedback value of a case in which a unit pulse is output. Thecontrol device 100 calculates a correction shift time using the responsecharacteristic data. The correction shift time calculated from theresponse characteristic data will be described below.

The control device 100 calculates the correction shift time and storesthe calculated correction shift time as a learning control parameter.

Operation of Control Device when Control Program Using Learning Resultis Executed

The control device 100 acquires the response characteristic data of thecontrol subject by executing the learning control parameter computationprogram and stores the learning control parameter as described above.

By executing the learning control program, the control device 100repeatedly calculates correction data using the calculated learningcontrol parameter from execution of the learning control parametercomputation program, and stores the obtained correction data as a resultof the learning control (FIG. 5).

The control device 100 calculates an instruction value using aninstruction value calculated from the instruction pattern, using thecorrection data obtained as the result of the learning control, and acorrection data obtained as the result of the learning control, andoutputs the instruction values in each control period. An instructionvalue that is likely to make a position deviation have a minimum valuewith respect to the instruction pattern that is a pattern that definesan operation of the target control subject is calculated using thecorrection data.

In S31, the control device 100 reads the instruction pattern andgenerates an instruction value.

In S32, the control device 100 reads the correction data, adds thecorrection data to the instruction value, and calculates a correctedinstruction value.

In S33, the calculated instruction value is output to the motor controldevice in each control period. The corrected instruction value isrepeatedly output to the control subject in each control period.

Correction Shift Time

FIG. 6 shows an example of a characteristic measurement pattern. Here,an example in which a unit time width pulse (a short pulse of a unittime width) is output as a characteristic measurement pattern is shown.FIG. 6 shows an example in which a unit time width pulse is input andresponse data thereof is acquired. Here, a unit time refers to a timewidth of a control period. Since the control period is 1 ms in theexample of FIG. 6, the example will be described below on the assumptionthat a pulse with a width of 1 ms is output.

In a case in which learning control is applied, in general, aninstruction value changes at each sampling time. Correction dataobtained in learning control is considered as a collection of amounts ofcorrected sampling times. For this reason, in learning control accordingto the embodiment of the present invention, a correction amount of aninstruction value corresponding to a certain sampling time is obtainedusing a deviation of the sampling time, and thereby appropriatecorrection data can be calculated through the learning control.

Since the correction amount of the instruction value is a pulse of eachsampling time, when a unit time width pulse is input, the correctionamount is obtained from response data of the sampling time that has themost significant influence.

It can be ascertained from the example shown in FIG. 6 that a responsedelay of 4 ms (a response delay characteristic) occurs in the unit timewidth pulse. The value thereof is set as a shift correction time.

FIG. 7 shows results of control over corrected instruction values usingthe shift correction time. Tracks of an instruction position, an actualposition, and a corrected position instruction value are shown in FIG.7. In addition, position deviation amounts of the instruction positionand the actual position are shown in FIG. 7. Furthermore, temporalchange of a correction amount of an instruction value is shown in FIG.7. As shown in FIG. 7, it is ascertained with regard to the actualposition and the instruction position that the corrected positioninstruction value causes a deviation between the actual position and theinstruction position to be minimized by using correction data of asampling time set back by the correction shift time.

FIG. 8 shows results of learning control performed on a control subjecthaving the characteristic of FIG. 6 as a response characteristic indifferent correction shift times. The calculation was performed on thecondition that learning control should be terminated in a case in whicha decrease rate of the sum of squares of position deviations between acorrected instruction value calculated from the instruction pattern anda feedback value is equal to or lower than 5%.

When a result of learning control performed in a correction shift timeset to 4 ms is compared to the results of learning control performed incorrection shift times set to 1 ms and 6 ms, it is ascertained that itis hard to approach a target operation even if learning is repeatedlyperformed when a correction shift time does not have an appropriatevalue for characteristics of a control subject.

In the present invention, by calculating a correction shift time that isa learning control parameter from a characteristic value of the controlsubject, learning control is performed in the appropriate correctionshift time, and thus it is possible to approach a target operation of amachine defined by the instruction pattern.

Modified Example of Calculation of Correction Shift Time

The response data with respect to the unit time width pulse is acquiredto calculate a correction shift time in the example of FIG. 5. Withregard to this, step response data S(n), in which n=0 to N, is measured,and then response data U(n) with respect to a unit time width pulseinstruction value may be obtained using the following calculationformula.

U(n)=S(n)−S(n−1),

wherein

n=0 to N, provided that, S(−1)=0

In addition, when a correction shift time is calculated, ramp responsedata R(n), in which n=0 to N, is measured, and then response data U(n)with respect to a unit time width pulse instruction value may beobtained through step response data S(n) using the following calculationformulae.

S(n)=R(n)−R(n−1),

wherein

n=0 to N, provided that R(−1)=0

U(n)=S(n)−S(n−1),

wherein

n=0 to N, provided that r S(−1)=0

Functional Configuration of Control Device

FIG. 9 shows a functional configuration of the control device 100according to the embodiment of the present invention. The control device100 includes an instruction value generation part 20, a learning controlpart 30, a control part 10, a characteristic measurement instructionvalue generation part 40, and a correction shift time calculation part50.

The instruction value generation part 20 reads the instruction patternand generates an instruction value on the basis of the read instructionpattern. Here, the instruction pattern is a target control value todefine an operation track of the control subject 2 that the target ofthe control system.

The control part 10 outputs a corrected instruction value obtained byadding the instruction value generated by the instruction valuegeneration part 20 to correction data generated by the learning controlpart 30 in each predetermined control period to drive the controlsubject 2.

The characteristic measurement instruction value generation part 40generates an instruction pattern for measuring a characteristic of thecontrol subject 2. When measuring a characteristic of the controlsubject 2, the control part 10 outputs a characteristic measurementinstruction value to the control subject 2 in each predetermined controlperiod.

The correction shift time calculation part 50 calculates a correctionshift time as a learning control pattern from a feedback value that isobtained from driving of the control subject 2 based on thecharacteristic measurement instruction value.

The learning control part 30 reads deviation data that is the differencebetween the instruction value generated by the instruction valuegeneration part 20 and the feedback value, and then repeatedly computescorrection data including a correction value to correct the instructionvalue.

The learning control part 30 computes a deviation between theinstruction value computes by the instruction value generation part 20and the feedback value input from the control subject 2. The learningcontrol part 30 further performs computation using the instruction valuecomputed by the instruction value generation part 20 and the feedbackvalue in each predetermined control period to obtain correction data ofa K+1-th instruction value using a K-th deviation data. Here, bycomputing the correction data using the deviation data obtained byshifting a response characteristic of the control subject 2 by thecorrection shift time, it is possible to calculate the correction datain accordance with the characteristic of the control subject.

The correction shift time may be a multiple of the control period or areal number.

Rev(k+1)(n)=Rev(k)(n)+G*Err(k)(n+st),

wherein

k: the number of learning times, k=0, 1, 2, . . .

n: sampling time, n=0, 1, 2, . . . , and N

Rev(k+1)(n): correction data at a sampling time n for k+1-th learningtime

Rev(k)(n): correction data at a sampling time n for k-th learning time

G: coefficient for deciding an intensity of learning

Err(k)(n+st): deviation data at sampling time n+st for k-th learningtime

st: correction shift time (an integer multiple of the control period)

The control part 10 adds the instruction value to a correction value andoutputs (transmits) the result to the control subject.

Library Program and User Program

Next, a configuration in which the control device of the presentembodiment performs calculation of a learning control parameter,learning control, and control of an operation track will be described.As an embodiment, the control device is easy beforehand with the libraryprogram that is appropriate for learning control and calculation of alearning control parameter. A user of the control device can generate acode for reading the library program using a support device of thecontrol device, which is not illustrated. If such a library program isprovided by the manufacturer of the control device or a third party inadvance, it is possible to produce a user program that enablescalculation of a learning control parameter suitable for a controlsubject in a short period of time. That is, the user program is used tocompute correction data obtained from an instruction pattern typicallyin learning control of the control device to control an operation trackof a control subject.

FIG. 10 shows an example of a library program executed by the controldevice according to the present embodiment. The library program mainlyincludes a learning control function block and a learning controlparameter computation function block. Some or all of the function blocksare instructions for assigning reading of a corresponding libraryprogram and execution after the reading when the execution orderarrives. In other words, a library program that is an actual state of aprogram corresponding to each function block is easy beforehand, and aprocessor appropriately calls and executes the library program inaccordance with a program. Functions of each function block will bedescribed below.

A characteristic measurement FB generates an instruction value forcomputing a response characteristic of a control subject, obtains afeedback value with respect to the generated instruction value, andthereby elicits a correction shift time as a learning control parameterfrom the response characteristic of the control subject.

Inputs of the characteristic measurement FB is defined that activationof a characteristic measurement mode, a maximum measurement time, and aninstruction value magnitude feedback value. The activation of thecharacteristic measurement mode is a signal for activating the presentfunction block, and when the signal indicates TRUE, the characteristicmeasurement mode starts, and TRUE is maintained during measurement ofthe characteristic. In the characteristic measurement mode, the controldevice computes the instruction value from the characteristicinstruction pattern, outputs the instruction value to the controlsubject, and sequentially stores the feedback values from the controlsubject. The maximum measurement time is a maximum time taken to measurethe feedback value from the output of the instruction value to thecontrol subject, and the feedback value of the control subject ismeasured for the maximum time from the control period in which thecharacteristic measurement instruction value is output and stored. Theinstruction value magnitude is an input for specifying a magnitude ofthe characteristic measurement instruction value to be output to thecontrol subject, and the characteristic measurement instruction valuehaving the magnitude of the instruction value for the maximummeasurement time is output in a pulse shape or a step shape.

The inputs of the characteristic measurement function block is furtherdefined as a feedback value. For the feedback value, a stored feedbackvalue is input in a measurement time given as the maximum measurementtime. A correction shift time is output by comparing a time of thecharacteristic measurement instruction value with a time of the feedbackvalue.

2. Learning Control Function Block

FIG. 11 shows an example of the learning control function block. Inputsof the learning control function block is defined as activation oflearning control. When the activation of learning control is TRUE, TRUEis output during the learning control.

The inputs of the learning control function block further include alearning end determination value, a correction shift time, aninstruction pattern (array data), and a feedback value. The learning enddetermination value is a real number given as a determination condition.The correction shift time is a value calculated by the characteristicmeasurement function block, and is an integer multiple of the controlperiod or a real number. The instruction pattern is given as array data.The feedback value is given as array data. The sum of squares ofposition deviations between the instruction pattern and the feedbackvalue is calculated and output as an evaluation function value.

The inputs of the control function block is further defined ascorrection data. For the correction data, the correction data isoutputted by adding a time shifted by the correction shift time to thedeviation of the instruction pattern and the feedback value, andcorrection data array is updated and output. When updating of thecorrection data array is completed, a learning end indicates TRUE as anoutput, and thus the activation of the learning control function blockends.

Effects

By providing the above-described learning control function block,characteristic calculation function block, and the library program forrealizing the blocks, it is possible to calculate a king board learningcontrol parameter for the characteristic of the control subject andgenerate the user program for performing learning control.

Supplement

In order to solve the above-described problems, the control deviceaccording to the present invention is a control device that controls acontrol subject and is characterized by including an instruction valuegeneration part that calculates an instruction value from an instructionpattern, a leaning control part that repeatedly calculates correctiondata including a correction value for correcting the instruction valuecalculated from the instruction pattern, and a control part thatcalculates a corrected instruction value from the instruction value andthe correction data and transmits the corrected instruction value to thecontrol subject, and the learning control part generates the correctiondata from a deviation between a feedback value with respect to thecorrected instruction value output to the control subject and theinstruction value computed by the instruction value generation part anda response delay characteristic of the control subject.

In addition, the control device according to the present invention mayfurther include a characteristic measurement instruction valuegeneration part, and a correction shift time calculation part thatcalculates a correction shift time to be used by the learning controlpart to perform learning control, and the correction shift timecalculation part may acquire a feedback value with respect to acharacteristic measurement instruction value generated by thecharacteristic measurement instruction value generation part andcalculate the correction shift time by comparing the characteristicmeasurement instruction value and the feedback value.

Furthermore, the control device according to the present invention mayhave the characteristic measurement instruction value that is a shortpulse of a part time width.

In addition, the control device according to the present invention mayhave the characteristic measurement instruction value that is in a stepfunction, and the correction shift time calculation part calculates thecorrection shift time by calculating a step response.

Furthermore, the control device according to the present invention mayhave the characteristic measurement instruction value that is in a rampfunction, and the correction shift time calculation part calculates thestep response from a ramp response and calculate the correction shifttime from the step response.

In addition, the control device according to the present invention mayhave the correction shift time that is a real number calculated from theresponse delay characteristic of the control subject.

The present invention is not limited to each embodiment described above,and can be variously modified within the scope of the claims, and thetechnical scope of the present invention also includes an embodimentobtained by appropriately combining another embodiment with eachdisclosed technical means.

REFERENCE SIGNS LIST

2 Control subject

10 Control part

20 Instruction value generation part

30 Learning control part

40 Characteristic measurement instruction value generation part

50 Correction shift time calculation part

100 Control device

1. A control device that controls a control subject, comprising: aninstruction value generation part that calculates an instruction valuefrom an instruction pattern; a leaning control part that repeatedlycalculates correction data including a correction value for correctingthe instruction value calculated from the instruction pattern; and acontrol part that calculates a corrected instruction value from theinstruction value and the correction data and transmits the correctedinstruction value to the control subject, wherein the learning controlpart generates the correction data from a deviation between a feedbackvalue with respect to the corrected instruction value output to thecontrol subject and the instruction value computed by the instructionvalue generation part and a response delay characteristic of the controlsubject.
 2. The control device according to claim 1, further comprising:a characteristic measurement instruction value generation part; and acorrection shift time calculation part that calculates a correctionshift time to be used by the learning control part to perform learningcontrol, wherein the correction shift time calculation part acquires afeedback value with respect to a characteristic measurement instructionvalue generated by the characteristic measurement instruction valuegeneration part and calculates the correction shift time by comparingthe characteristic measurement instruction value and the feedback value.3. The control device according to claim 2, wherein the characteristicmeasurement instruction value is a short pulse of a unit time width. 4.The control device according to claim 2, wherein the characteristicmeasurement instruction value is in a step function, and the correctionshift time calculation part calculates the correction shift time bycalculating a step response.
 5. The control device according to claim 2,wherein the characteristic measurement instruction value is in a rampfunction, and the correction shift time calculation part calculates thestep response from a ramp response and calculates the correction shifttime from the step response.
 6. The control device according to claim 2,wherein the correction shift time is a real number calculated from theresponse delay characteristic of the control subject.
 7. The controldevice according to claim 3, wherein the correction shift time is a realnumber calculated from the response delay characteristic of the controlsubject.
 8. The control device according to claim 4, wherein thecorrection shift time is a real number calculated from the responsedelay characteristic of the control subject.